I'm going to be advising my parents about what credit cards they should get to earn points/miles to use on United for their trip EWR-HNL-LAX-EWR next year. They are both under 5/24 and already have the CSP. I'm thinking: Ink Business Preferred, Chase Freedom Unlimited, and then United Explorer (maybe United Club if it's closer to the trip so they can use the UCs at each of their stops) in that order? What's everyone's thoughts?
Welcome to the thread! You've come to the right place, and you'll find a lot of friendly, helpful advice here.
Just a few questions to start --
Have you sold them on the idea of taking advantage of credit card signup bonuses to offset travel costs? Some people are very wary of credit cards in general.
Are both your parents game to sign up for credit cards (2-player mode)?
This way, they can double up on the signup bonuses and earn referral bonuses by referring each other. For example, the Chase Ink Business Preferred ("CIP") has a 80,000 Ultimate Rewards ("UR") points signup bonus. If one parent gets this card, that's 80k UR. If that parent refers the other parent, that's 20k UR for the referral and another 80k UR for the second card. Combined, that's 180k UR, which has a cash value of $1,800; but if they use the points to book travel through the Chase UR travel portal using either the CSP or CIP, they're worth 25% more or $2,250 towards flights, hotels, car rentals, and activities.
What's their precise */24 count?
What cards do they already have? And when (month/year) did they open them?
Do both your parents have the CSP, or just one?
The reason being the Chase Sapphire Reserve ("CSR") might be a better card to have, if at least for a year, because it offers a 50% greater redemption value on UR points (vs. 25% on the CSP and CIP). The CSR also comes with a 50,000 UR signup bonus.
However, last year, Chase implemented a new rule we call the "One Sapphire Rule," meaning you can only hold one open Sapphire card at a time. While your parents have a CSP, they can't apply for the CSR or that application will be denied.
If only one parent has the CSP, the other parent can apply for the CSR. Here, a lot of us would actually suggest applying for the CSP
and CSR together, on the same day, to "double dip" the two cards' signup bonuses as this is the only trick to get both cards (for their bonuses) and work around the One Sapphire Rule.
When did your parent(s) get the (one, or two?) CSP(s)?
The other part of the One Sapphire Rule is you're only eligible for a signup bonus from a Sapphire card (CSP, CSR) if you haven't already received a bonus on any other Sapphire card within the last 24 months.
For the parent(s) who has or have the CSP, when did they open it? If it's been more than two years ago (and 24 months after they received the signup bonus on that CSP), they can call Chase at the number on the back of the card and ask they "product change" the CSP to the Chase Freedom Unlimited ("CFU") you were thinking of getting for them. This way, your parent(s) no longer have an open Sapphire card (see above) that would block them from applying for a new CSP and/or the CSR and getting those better signup bonuses. Also, you won't waste a */24 slot on a new CFU when you could be using that slot on cards with higher signup bonuses like another CSP (currently offering a 60,000 UR signup bonus) and/or the CSR (currently offering a 50,000 UR signup bonus).
If you'd like both the CSP's 60k UR bonus and CSR's 50k UR bonus, you'd typically be barred by the One Sapphire Rule (only one Sapphire card at a time; only one Sapphire bonus within a 24 month period). Currently, the only way to get around the One Sapphire Rule is to apply for both the CSP and CSR on the same day.
Again, if each of your parents are game to sign up for their own credit cards (never make each other an authorized user because that will take up a */24 slot; just get the other parent their own card), think about how one parent can sign up for a card first, then refer the other parent to that same card. This way, you're doubling up on the signup bonuses and getting the referral bonuses.
How do they feel about annual fees ("AF")? And can you convince them that annual fees are worth it if you can show the benefits from holding the card for just one year outweigh those fees? For example, the CSR has a $450 AF, which is a sticker shock to a lot of people, but it comes with a 50,000 UR signup bonus, which has a cash value of $500, worth $750 when redeemed for travel through Chase; and a $300/year travel credit that can applies to anything that codes as travel and can be used twice on a single AF.
As for the United MileagePlus Explorer ("MPE"), it's a good card since your parents are near a United hub like EWR. It'll give them additional award seat availability. They'll get a free checked bag if they buy their tickets from United on the card (which may or may not be the best deal). The current signup bonus is 50,000 UA miles, which is a decent offer. However, a targeted signup bonus was as high as 70,000 UA miles for most of last year, with 50,000 UA miles being the public offer. I believe it dropped down to 40,000 UA miles last fall and now it's back up to 50k. Be aware of historical offers in weighing whether it's a good time to apply.
If one or both your parents plan to get the MPE, I don't see why they would need the MileagePlus Club card. Yes, the Club card comes with a 50,000 UA miles signup bonus and access to United Club lounges, but it carries a $450 AF. I think a */24 slot and that AF can find better value elsewhere. The MPE already comes with 2 United Club passes after account opening and every anniversary thereafter. If each of your parents get their own MPE, that's 4 passes a year. If you really want more access to the United Clubs, you can find passes going for $25-30 each on eBay. Or a one-time pass is $59 direct from United.
I'd note that if you want a nice place for your parents to relax and refresh in between flights, and they decide to apply for the CSR, the CSR comes with Priority Pass, which allows the cardholder and all guests in his/her traveling party to access their network of airport lounges free.
We had previously decided this would be an off year for us since we're doing the big family vacation to Disney in 2019. I thought about it though and I'm really not sure that a big Disney trip is something I want to spend the money OR points on this year. I realized the other day that, so long as I get approved for the CIP later this year, we will have enough points to cover rooms onsite for 6 adults even if we earn don't any additional URs for the rest of the year. So I'm really thinking I don't want to sacrifice the URs when I know I will appreciate those more when trying to foot a big Disney bill in 2019. 
